Ishak, M. Y.

Kumar, Vijay

Quah, Soon Cheang

Tan, Soon Guan

Universiti Putra Malaysia Institutional Repository

FOR Category F10800: Biological SciencesGENETIC STUDIES OF THE ASIAN SUBGENUSCERATOTROPISS.C. Quah, S.G. Tan, S.V. Kumar and M.Y. Ishak.Department of BiologyUniversiti Putra Malaysia, 43400 UPM, Serdang, Selangor,Malaysiaand Monash University Sunway MalaysiaKeywords: cytogenetics, population genetics, nodula-tion, breeding systems, Asian Ceratotropis.IntroductionCeratotropis is the most important subgenus under the genusVigna and comprised of five major crops such as mungbean,black gram, adzuki bean, rice bean and moth bean. Its biodi-versity includes wild species such as V. trinervia, V. minima,V. reflexo-pilosa, V. radiata var sublobata, V. grandiflora,and V. umbellata var gracilis. Genetic studies of Cera totro pisare important in that desirable genes from wild species couldbe incorporated into cultivated forms of the subgenus to en-hance its commercial value. In Malaysia, preliminary collec-tions of three wild species have been made by Bujang et al.(1994a; 1994b). A total of 183 accessions has been collectedand evaluated using electrophoresis. Very little is knownabout the genetics of Asian Ceratotropis especially itsbreeding systems, cytogenetics, nodulating habits, generalstructure of populations and its phylogenetic relationships. Inthe present study, isozyme analysis and random amplifiedpolymorphic DNA (RAPD) marker assay were used toevaluate both wild and cultivated species of Ceratotropis.Materials and MethodsIs?zym.e analysis was used to evaluate collections of Vignatrinervia from four locations in Peninsular Malaysia while~evelopme?t .of RAPD protocols were performed using cul-tivated vanenes of Vigna radiata. In the case of isozymes,~xtracts of the seeds collected from Bentong, Muar andan?kak (Ladang Bekoh and Tangkak) were subjected tovertical polyacrylamide gel electrophoresis at 4°C and thegels were stained for the different enzymes. The data col-lected were analysed using the BIOSYS-l computer package.A total of 15 varieties and varietal crosses of mungbean wereused for the development of RAPD protocols. GenomicDNA was extracted from each variety using the ClontechLaboratories DNA extraction kit before RAPD protocolswere developed. Twenty short arbitrary oligonucleotides (10-mer) with a 60-80% GC content from Operon Technologies(KitA) and ten arbitrary 16-24 mer oligonucletides with a GCcontent of 45-70% from Genosys Inc. were screened for PCRamplification and optimised to generate reproducible bandingpatterns.Results and DiscussionIsozyme analysis revealed 13 loci for seven enzymes Alcoholdehydrogenase (ADH-l), Aldolase (ALD-l), Esterase (EST-1, EST-2 and EST-3), glutamate dehydrogenase (GDH-l),Malate dehydrogenase (MDH-l and MDH-2), Octonol dehy-drogenase (ODH-l), Glucose-6-phosphate dehydrogenase(G6PD-l) and general proteins (GP-I, GP-2 and GP-3) forVigna trinervia accessions (Qua1I and Ishak,1998). Five ofthe 13 loci were polymorphic and were associated with ESTM~H an~ ~P systems. The re~ults showed a low level of ge~netic variation among the VIgna trinervia accessions. Thehighest genetic distance of 0.025 was observed between thepopulations from Muar and Tangkak (Ladang Bekoh) whilethe least distance of 0.003 was detected between populationsfrom Tangkak (Town centre) and Bentong. The dendogramshowed that Vigna trinervia could be positioned into twoclusters, with one cluster for populations from Bentong,Tangkak (Ladang Bekoh) and Tangkak (Town centre) whilethe Muar population was confined to the second cluster. Theoptimised RAPD protocol using five short primers, OPA-Ol,OPA-04, OPA-06, OPA-15 and OPA-17 have been success-fully applied to identify polymorphisms in the 15 varietiesand varietal crosses (Kumar et al. 1998). The five primersmanaged to reveal genetic polymorphisms between andwithin different varieties and their crosses. However, morevarieties and crosses will have to be studied before the ge-netic distances could be calculated and a phylogenetic treedrawn. The ten long arbitrary primers used were found toamplify mungbean DNA but the results were not as repro-ducible. Further optimisation need to be resolved before itcould be used to differentiate mungbean accessions.ConclusionsBoth isozyme and RAPD markers are useful for geneticevaluation of mungbean. They could be used to complementother conventional approaches to improve breeding strategiesin national breeding programmes.ReferencesBujang, I., Egawa, Y., Tomooka, N., Tan, S.G., Abu Bakar, H.A.,and Anthonysamy, S. 1994a. Exploration, Collection and Elec-trophoretic Variants of Wild Vigna (subgenus Ceratotropis) inPeninsular Malaysia. In: M.K. Vidyadaran and S.C. Quah (eds).Applied Biology Beyond the Year 2000. Proceedings of the 3rdSymposium of Malaysian Society of Applied Biology, Melaka. p.51-55.Bujang, I., Egawa, Y., Tomooka, N. and Quah, S.C. 1994b. WildVigna (subgenus Ceratotropis) species in Peninsular Malaysia.In: C.L. Koh (ed). The Role of genetics in National Development.Proceedings of The First National Congress on Genetics, KualaLumpur. p. 198-200.Kumar, S.V., Quah, S.C. and Tan, S.G. 1998. Development of Ran-dom Amplified Polymorphic DNA Markers in mungbean (Vignaradiata). In: Moharnad Osman et al (eds). Genetics TowardsBetter Quality In Life. Proceedings of the Third National Con-gress on Genetics, UKM, Bangi. p. 239-241.Quah, S.C and Ishak, M.Y. 1998. Isozyme variation in Vigna triner-via populations in Peninsular Malaysia. Malaysian Applied Biol-ogy. 27 (Suppl): 99-102.Supported by IRPA Grant 09-02-04-0004195

Genetic studies of the Asian subgenus Ceratotropis

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Genetic studies of the Asian subgenus Ceratotropis

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